RRC ID 35644
著者 Klein G, Kobylak N, Lindner B, Stupak A, Raina S.
タイトル Assembly of lipopolysaccharide in Escherichia coli requires the essential LapB heat shock protein.
ジャーナル J Biol Chem
Abstract Here, we describe two new heat shock proteins involved in the assembly of LPS in Escherichia coli, LapA and LapB (lipopolysaccharide assembly protein A and B). lapB mutants were identified based on an increased envelope stress response. Envelope stress-responsive pathways control key steps in LPS biogenesis and respond to defects in the LPS assembly. Accordingly, the LPS content in ΔlapB or Δ(lapA lapB) mutants was elevated, with an enrichment of LPS derivatives with truncations in the core region, some of which were pentaacylated and exhibited carbon chain polymorphism. Further, the levels of LpxC, the enzyme that catalyzes the first committed step of lipid A synthesis, were highly elevated in the Δ(lapA lapB) mutant. Δ(lapA lapB) mutant accumulated extragenic suppressors that mapped either to lpxC, waaC, and gmhA, or to the waaQ operon (LPS biosynthesis) and lpp (Braun's lipoprotein). Increased synthesis of either FabZ (3-R-hydroxymyristoyl acyl carrier protein dehydratase), slrA (novel RpoE-regulated non-coding sRNA), lipoprotein YceK, toxin HicA, or MurA (UDP-N-acetylglucosamine 1-carboxyvinyltransferase) suppressed some of the Δ(lapA lapB) defects. LapB contains six tetratricopeptide repeats and, at the C-terminal end, a rubredoxin-like domain that was found to be essential for its activity. In pull-down experiments, LapA and LapB co-purified with LPS, Lpt proteins, FtsH (protease), DnaK, and DnaJ (chaperones). A specific interaction was also observed between WaaC and LapB. Our data suggest that LapB coordinates assembly of proteins involved in LPS synthesis at the plasma membrane and regulates turnover of LpxC, thereby ensuring balanced biosynthesis of LPS and phospholipids consistent with its essentiality.
巻・号 289(21)
ページ 14829-53
公開日 2014-5-23
DOI 10.1074/jbc.M113.539494
PII S0021-9258(20)38684-1
PMID 24722986
PMC PMC4031536
MeSH ATP-Dependent Proteases / genetics ATP-Dependent Proteases / metabolism Amidohydrolases / genetics Amidohydrolases / metabolism Base Sequence Blotting, Western Cell Membrane / metabolism Escherichia coli / genetics Escherichia coli / growth & development Escherichia coli / metabolism* Escherichia coli Proteins / chemistry Escherichia coli Proteins / genetics Escherichia coli Proteins / metabolism* Gene Expression Regulation, Bacterial Genes, Essential / genetics Glycosyltransferases / genetics Glycosyltransferases / metabolism HSP70 Heat-Shock Proteins* / genetics HSP70 Heat-Shock Proteins* / metabolism Heat-Shock Proteins / chemistry Heat-Shock Proteins / genetics Heat-Shock Proteins / metabolism* Hot Temperature Lipopolysaccharides / biosynthesis* Lipopolysaccharides / chemistry Membrane Proteins / chemistry Membrane Proteins / genetics Membrane Proteins / metabolism* Models, Molecular Molecular Sequence Data Molecular Structure Mutation Protein Binding Protein Structure, Tertiary Reverse Transcriptase Polymerase Chain Reaction
IF 4.238
引用数 32
WOS 分野 BIOCHEMISTRY & MOLECULAR BIOLOGY
リソース情報
原核生物(大腸菌) JW3596-KC JW0175-KC